Electrical transmission system



0, 1935. R; M. SOMERS 2,011,953

ELECTRICAL TRANSMI SSION SYSTEM Filed July 10, 1931 2 sheets-Sheet 1 FIG. 5.

l 6/ 7 ,n 2/46 I I l 8 l I RADIO RECHVER 20 FIG. 3

R.F. Umr' 19 ,J u 18 I 50 Y Pb'wm Rccnnaa UNIT M417 v mtkw Aug. 20, 1935. R. M. SOMERS ELECTRICAL TRANSMISS ION SYSTEM Filed July 10, 1951 2 Sheets-Sheet 2 INVENTOR flQ/uwd- M. (9M

BY/M ATTORNEY {UNITED STATES Patented Aug. 20, 1935 PAT T OFFICE ELECTRICAL TRANSMISSION SYSTEM Richard M. Somers, EastOrangaNi J., assignor to Thomas A. "'Edison, Incorporated, West J range, N. .L. a corporation of New-Jersey Application July10, mar-swarm. 549,872

13 claims. oi. 2501-1-20), 1'

put from a remote point. 1

His well known that electrical signalling sy sa terns and especially (radio broadcast receivers maybe adjusted to select any one of a plurality inthe receiver. Y if of signals on various frequency channels; This selection is accomplished by "tuning elements mounted to operate as a singleunit. The tuning, unit may be manually operated or driven by a motor under control of circuit switches at a remote point. 1 Y a I v The present invention is applicable to such a remote control system wherein energization of the motor which drives the "tuning instruments is under control of a variable frequency oscillator at the remote position.- In brief, an os-,

cillator is'adjusted to generate any one of aband of frequencies corresponding in range to'the 'rangeof the receiver. The transmission of the oscillator frequency tothe receiver controls the driving motor. The motor'is energized by simply closing a relay circuit at the remote position, the motor being-stopped at the correct tuning point when the receiver tuning instruments reach a position such that the'receiver' is tuned to the oscillator frequency, preferably by means of arelay responsive to change of plate current Preferably, the relay is arranged to stop the movement of 'the'tuning instruments only when the receiver reaches exact resonance with the oscillatorfrequency. I

'Thefeatures of novelty which- I believe to b e characteristic of my invention are set forthwith particularity in the appended claims. My invention itself, however; both'as to its fundamental v amplifiers and the power'supply device, if deprinciples, and as to its particular embodiments fwill best be understood by'reference to the specification and accompanying drawings, in which:

" ;'-Fig.-- l is a'diagrammatic drawing of areceiver system" equipped with remote control apparatus in accordance with my invention. I

Fig. 2 is a schematic circuit diagram; and

Fig.3 is a detail view of one form of modification of the circuitpf-Fig; 2. 1 a i Referring now more particularly to Fig. 1, a

letters isshown. There is also provided a start switch I4, tuning switoh 15, volume control it and tuning operating lamp'tl'i.

radio. receiver 5 preferably connected to an an- It is to be understood that any other panel arangements may a be employedv without departinglfrom thespirit of the invention. The corresponding elements '15 just mentioned are similarly numbered inFig. 2

Referring to Fig." 2, the receiver, unit is shown in two sections asa radio frequency amplifier unit. (which-maytinclude the detector) and an audio frequency amplifier unit 2 l. of these amplifiers are well known in the art and form, per'se, nopart of my present invention, they are not describedin detail. The output of the radio frequency unit is supplied to Since both 20 the input'of the audiov frequency unit by-conductors 23., A motor of any suitable type is mechanically connected by a shaft to the tuning elements (not shown), which are usually variable condensers. A reversing cam 26 reverses the direction of rotation of the motor 24 after each 180 rotation of the condenser shaft but-the system may be arranged for a full 360 rotation of the tuning condensers. The motor is energized over conductors 21, 2B, 29 and 3!! through contact switches 3|,and 3Z 'fromf secondary 34 of 5 j power transformer 35.

The receiver units are preferably energized from apower -packz3'l which in turn is supplied over conductors 38from secondary 3911f the power transformer." The third secondary M of the 40 -power transformer is. tapped and supplies the filamentlof oscillator tube 42 through conductors 43'and signal lamp l1 over conductor l, switch 45 and one of the conductors A3, as well as the filaments of the various tubes of theradio and audio 45 sired. The power pack '31 also supplies anode potential'for tube 42 over'conductor' ll which includes the winding of relay 48, a manual switch l5 and winding. 50. The relay 48 has an armature. 5| which controls contacts 53, 54, 3t, and 56: contact 53 connecting and disconnecting the antennat to and from the unit 20; contact 54 connecting and disconnecting the 'oscillatoroutputfto and from the unit 20 over conductor 58; v,

i r The operation of thecircuit-is closingimain power switch'l'l, the receiver is contact 3| controlling the power supply to motor 24; and. contacts and 56 controlling the transfer of the output of unitHZI from loud speaker 8 to a circuit including a relay 60, rectifier BI and series tuning elements 62 and 63 and vice versa,

thistransfer being done over conductors 65, 66

and G1. 7

Referring particularly to the oscillator circuit, this may include coupling inductances 50 and 69 with tuning element lZa controlled by knob I2 in Fig. l. The time constant of grid leak H and condenser 12 may be such as to start and stop high frequency oscillationsi'at an audible. rate, thereby introducing self-modulation of an audible frequency. This audible note may be for, example 1000 cycles. Blocking condensers l4 and 15 keep the direct current from the'igri d of tube 42 and the receiver input circuit, respectively;

Other types of oscillators may be employed in this.

invention such as the usual type high frequency oscillator or the combination of high: frequency andlow frequency oscillators with intermodulation. The volume control rheostat 16 may control the bias on the radio frequency amplifier tubes or may be inthe receiver input circuit, connection being made over conductors 16, or a separate motor may be provided, c'ontrolled'by volume increase and decrease switches. I

as follows: By

48 connects the oscillator output circuit 58 to the receiver unit 26 by making contact 54 and simultaneously disconnects the... antenna 6 from the receiver unit by breaking contact 53 :thereby rendering such unit unresponsive to radio broadcast signals and'indeed to any electrical disturbances or effects extraneous to thereceiver unit excepting only those originatedby the oscillatonof control unit ll. Simultaneously, contact 3| is made completing the motor energizing circuit over conductors 27, 28, 29; and'30 and rotating the, tuning condensers. Also, simultaneously contact. 55

, is broken, disconnecting the speaker 8 from the low frequency amplifier unit 2|, and contact 56 is made connecting this unit in circuitxwithrrelay 65, rectifier 6,! and filterelements 62 and63.

The circuits remain as just'described until the Y tuning condensers havebeen adjusted to pass 710 kilocycles, at whichinstant the receiver is tuned to the,oscillator frequency and the '1000 cycle a component thereof is amplified in audio amplifier This component is rectifiedflby rectifier (to ,operate the direct current relay 60.1Oper'ation of relay 5%] breaks contact 32 which disconnects,

motor 25 from its power supply, stoppingthe tuning condensers to receive any signal on "710 kilos cycles. Simultaneously, contact 46 isbroken, be-

ing on the sarne'arm-ature, this contact opening the supply circuit to lamp l'l.

When lamp I? is extinguished, the operator, at

unit it is informed that the receiver has beentuned and switch 15 is then opened; This action tie-energizes relay 48, restoring the, contacts to normal as shown in the circuit. That is, unit 20 is connected to antenna 6 and disconnected from the oscillator, contact 3! is broken which again 7 breaks the motor power supply circuit, and contacts 55 and 55 are respectively made and broken disconnecting the unit 2| from the relay and connecting it to the speaker 8. It is obvious that de-energization of relay 60 makes the motor supply circuit contact 32 butl'as this circuit is broken at contact 3i,-the motor isnot energized. The making of contact 45, however, again lights the lamp I1, indicating that the circuit is normal.

It is to be noted that although there appear to be several operations, they occur either simultaneously or in extremely rapid sequence, complete tuning being accomplished rapidly.

When an unmodulated oscillator is employed with the relay 6! located as shown in Fig. 2, contact 53 is always made in order to obtain a beat frequency in the audio range. In this case the oscillator is calibrated to correspond with the broadcast frequency range but it will be under- .stoodnthat it will differ in its tuning from the tuning ofpthe receiver by the frequency of the beat note.

,In Fig. 3 a circuit modification is shown in which therelay fillof' Fig. 2"is in shunt to a resistance l8 in'the platesupply circuit for the radio frequency unit 2&3. A. rectifier I9 permits theidirect-xcurrent relayto operate from alternating. current inthe plate circuit. The filter 52, 63 (Fig. 2) may also be used, preventing operation. of-relay Silby static or other extraneous receiver noises, the filter being tuned to the 1000 cycle audio note in Fig/Zand to the beat .note'in Fig. 3. x v V r Although the invention has been described in its preferredembodimenta'it will. be understood that ;modifications and changes may be made ;without; -departing from thespirit andscope of my invention, as will be understood .;by those skilled in the art.- i

I claim:,,- 1. In anelectrical signalling system, in combilnationya receiver having a signal selector which dsadjusta'ble to efiect tuning of the'receiver to any of a plurality of signal frequencies, electromotive means for adjusting such signal selec- .-tor, 'a local-source of high frequency currents normallyphysically connected to said receiver,

.means for initiating'operation of said adjusting means and for simultaneously rendering said receiver responsive only to currents from said source, and means in acircuit of saidreceiver controlled by currents from said source for interrupting the operation of said adjusting means when said receiver is tuned to a definite relation with the high frequency currents from. such sourced v a -2. In anelectrical signalling system, in combination,a receiver having aysignal selector which is adjustable to eifect tuning of the receiver fzto any of a plurality of signal frequencies, elec :llI'O m0 tiV6 means for adjusting such signal selector, an "oscillator normally physically connected "to said receiver, means for controlling the oscillator frequency, .means for -initiating operation of said adjusting means and. for simultaneously ;rendering said; receiver responsive only to currents-generated by said oscillator, and means in a circuit of said receiver controllable bycurrents from said oscillator for stopping adjustment of said signal selector'at resonance with the oscillator frequency.

3. In an electrical signalling system, in combi- ,nation,.a receiver having, a-signal selector which is adjustable to effect tuning of the receiver to any of a'plurality of signal frequencies, electro- *rnotive means for adjusting such signal selector,

an oscillator normally physically connected to ing said receiver responsive only to currents from said oscillator and means electrically connected, during adjustment of said signal selector, in a circuit of said receiver and responsive to currents from said oscillator for terminating adjustment of said signal selectorwhen resonance with the oscillator frequency is'robtained.

4. In a signalling system, in combination, a receiver comprising tunable circuits for selecting signals, power means for varying the tuning of 7 said circuits, a circuit for energizing said power means, a relay energizable from the output of said receiver to open said circuit, an oscillator normally physically, connected to said receiver, and means whereby oscillator currents-will be supplied to said receiver and the receiver Will be rendered responsive only to currents from the oscillator whenever said power means is operating to vary the tuning of said tunable circuits. 5. In a signalling system, in combination, a receiver comprising tunable, circuits for selecting signals, power means for varying the tuning of said circuits, a. circuit for energizing said power I means and comprising a relay for interruptingv such circuit, connections for energizing said relay from the output of said receiver, an oscillator means and comprising a relay for interrupting such circuit, connections comprising a rectifier forenergizing said relay from the output of said receiver, an oscillator normally physically, connected to said receiver, and means whereby oscillator currents will be supplied to'the input ofv said receiver and the receiver will be rendered responsive only to currents. from the oscillator,

whenever said'pow'ermeans is operating to vary mally physically connected.- to said receiver, means whereby during tuning of the said re-' ceiver, said oscillator is electrically connected to the receiverand the receiver is rendered responmined relation with the frequency ofthe oscillator. I

8. In an electrical signalling system, the combination of a. receiver having adjustable tuning elements, a motor for adjusting said elements, an I oscillator normally physically connected to said' receiver and independent as to its frequency of the receiver, an input circuit for said receiver,

means for electrically connecting said oscillator tosaid input circuit and for rendering said receiver responsive only to currents from the oscillator when the oscillator is energized, and means. controlled by the current in a circuit of said receiver and rendered operative to de-energize said motor only upon the receiver being tuned to a predetermined relation withthe'fr'e quencyo-f the oscillator. r

9. In a broadcast receiver system, the combination of a receiver unit having tuning elements, a

loud speaker for said unit, an antenna for said unit, a motor for adjusting said tuning elements, an oscillator normally independent of said receiver'unit, and means for coupling the output of said oscillator to said receiver and for concurrently disconnecting said loudspeaker and said antenna from said receiver unit and energizing said motor when'said oscillator is energized.

. 10. The method of tuning a radio receiver from a remote position comprising generating at said remote position currents of a frequency corresponding to any selected one of a. pluralityof broadcast station frequencies, simultaneously conditioning the receiver so that it can be affected only bythe .currents generated at such remote position, impressing the said currents corressponding to said selected frequency 'onsaid receiver, adjusting the receiver tuningelements, and utilizing the current in a circuit of said receiver to terminate the adjustment of said tuning I 7 elements.

1,1. The method of tuning radio receiving apparatus to any selected'one of a plurality of different frequencies which comprises generating at a position remote from'said apparatus currents of a frequency having apredetermined relation to the selected frequency, simultaneouslyconditioning the receiving apparatus so that it can be affected only by currents generated at such remote position, impressing such generated. ourrents on the receiving apparatus, varying the tun- ,ing of the receiving apparatus and utilizing the output of the receiving apparatus to terminate variation of its tuning. r

r 12. The method of adjusting a radio receiver to i any selected one of a plurality of different frequencies which comprises generating currents of a frequency having. a predeterminedrelation to the selected frequency and simultaneously condi-. tioning the receiver so that it can be affected only by currents of a frequency having said predetermined relation, impressing said currents on said receiver, simultaneously varyinggthe tuning of said receiver, utilizing the output'of said receiver to stop the variation of its tuning, and terminate ing the impressionofsaidcurrents on saidre ceiver when the latterhas been tuned to the means for actuating said tuning means, a loud speaker and an antenna for said receiver, an

oscillator located remotely 10f said receiver unit, means for connecting sa'idoscillator to said receiver and for concurrently disconnecting said loud speaker and said antenna from said receiver, and energizing said actuating means when said oscillator is energized, anoutput circuit for said receiver, and means in said output circuit for de-energizing said actuating means when said receiver unit is tuned to the frequency of said oscillator. l

RICHARD son nns. 

